Breeding Potential
The breeding potential of Centropyge is excellent. Not only are they small, hardy and easily paired but those species that adapt well to captivity will often spawn without any special provisions. In fact, aquarium spawning is frequently witnessed by hobbyists and has been documented for more than 14 species.

In nature, the reproductive strategy of Centropyge is to produce a moderate number of small eggs, daily, over a long reproductive life span. However in captivity, egg production can be poor and random when the proper diet and environmental conditions are lacking. In our experience, there are a number of key criteria to consistently achieving consistent, large, quality, fertile spawns.

Tank Size
First off consider the size and height of the spawning tank. A pair or trio of an average sized Centropyge species, like the flame and lemonpeel angel, should be kept in a minimum volume of 50 gallons. Smaller species, like the Fisher’s angel, need little more than 30 gallons. We have found that egg fertility greatly improves when Centropyge are given enough room during the final rise that culminates in spawning. Therefore, the height of the water column in all of our Centropyge broodstock tanks is at least 20 inches. As for infrastructure, we provide a little bland décor in the form of pots or tiles for hiding but also leave adequate room not to restrict courtship behavior. Our best spawning results thus far have been attained in standard, 3-foot high 55-gallon drums and 4x2x2 foot, 120-gallon aquariums. Each of the aquariums contains two pairs separated by a divider.

Lighting and Temperature
Lighting and water temperature are important parameters when conditioning fish to spawn. As in all reef fishes, the reproductive cycles of Centropyge are closely tied to environmental cues. Warm water temperatures and long days induce gonadal maturation and reproductive behavior. Tropical species (example: C. flavissimus , C. bicolor and C. bispinosus) will spawn periodically throughout the year, while those experiencing seasonal changes usually have a distinct breeding season. For example, the Japanese pygmy angel, off southern Japan, and the Potter’s angel, off Hawaii, only spawn in the spring and summer months when daylight exceeds 13 hours and temperatures are or rise above 26°C. During their spawning period Centropyge species reproduce daily. Courtship is thought to commence near late afternoon and culminate at dusk.

To induce reproduction we provide a light period of 15 hours at anywhere from 1-3 watts per gallon. Light intensity is reduced during the last two hours to create a crepuscular effect, though this is not necessary once the fish have begun to spawn regularly. Water temperatures are maintained near 28°C for tropical species and 26°C for sub-tropical ones. Winter-like conditions are created for 1-2 months every year by reducing the light period by 3 hours and temperature by 3°C. This change inhibits reproduction and gives our broodstock a well-deserved rest.

Nutrition
Providing the right nutrition is critical, not only to keep a pair healthy but also to obtain a good quantity of fertile eggs. In nature, Centropyge have a non-specialized diet, feeding primarily on algae, detritus and interstitial fauna. In the aquarium they should be provided with a balanced diet. Conventional aquarium foods such as frozen, chopped seafoods, quality flakes and pellets and commercial gel diets containing algae are adequate. we’ve had best results conditioning our broodstock on 2-3 daily feedings of a diverse seafood gelatin diet, rich in vitamins, pigments and highly unsaturated fatty acids. Important ingredients include fresh fish and shrimp, fish roe, a multi-vitamin mix, spirulina and astaxanthin. In addition, we allow for ample growth of golden diatoms (brown algae) in the aquarium. Species that rely heavily on detritus and small benthic fauna in their diet (C. potteri, C. interruptus ), are kept in tanks that are less frequently cleaned and set up with sand plenums. The Japanese pygmy angel has actually been observed feeding directly on fecal material of other reef fishes in the wild.

Water Quality
Last but not least adequate water quality needs to be maintained. This means the system should have an established nitrogen cycle (no ammonia or nitrite and nitrate levels below 50 mg/L), a specific gravity between 1.020 and 1.024, (the lower end of this is more ideal), a pH near 8.2 and the appropriate water temperature and lighting (as discussed earlier).

Most of the system at our facility are connected and have central filtration. Some are isolated as individual systems. Each system is designed to be simple, efficient and easy to clean. The water is recirculated through a sump in which a 5 um bag filter removes particulates. Since the bio-load is small, a standard sand plenum provides ideal biological filtration. The plenums are either built into the sumps or tanks themselves. All tanks with bare bottoms are siphoned daily while those with in-tank plenums are cleaned once a month. A 50 percent water change is done every 2-3 months.

A barrel system for spawning smaller Centropyge species

Egg Collection
The females typically produce between 300 and 2000 fertile eggs every night. Collecting pelagic eggs is relatively easy since they are buoyant. Our broodstock tanks have surface outflows that spill into a collecting tank where the eggs are concentrated in a screened container over night. In the morning they are washed into a 1-liter beaker with fresh saltwater. Pelagic eggs that die during development will sink to the bottom as will any unwanted material, such algae or leftover foods. Healthy, fertile eggs remain buoyant and accumulate at the rim. These can then be carefully transferred with a pipette into the larval rearing tank before they hatch.

Fertile Centropyge eggs in one-liter beaker